This relates generally to displays, and, more particularly, to organic light-emitting diode displays.
Electronic devices often include displays. Organic light-emitting diode displays may exhibit desirable attributes such as a wide field of view, compact size, and low power consumption. Organic light-emitting diode displays may have individually colored light-emitting diodes such as red, green, and blue diodes or may use an array of white diodes with an overlapping array of red, green, and blue color filter elements. Organic light-emitting diode displays that are based on white diodes may be fabricated using fewer evaporation masks than are generally used when forming a display based on red, green, and blue diodes.
White diodes may be implemented using a tandem design in which a first diode and second diode are arranged in series. The first diode may be a blue diode and the second diode may have a yellow emissive layer or a stack of red and green emissive layers. The light produced by the first and second diodes in each tandem organic light-emitting diode collectively forms white light emissions that can be filtered using an overlapping color filter element. Organic light-emitting diodes with tandem designs may be operated at reduced currents relative to other designs and may therefore exhibit extended lifetimes.
It can be challenging to form a white diode organic light-emitting diode display with a desired color gamut. Color gamut can be enhanced by using narrowband color filter elements, but this adversely affects power efficiency. The reproduction of blue image content can be particularly challenging. White diodes generally contain blue emissive material, but due to the relatively low efficiency available from the blue emissive material, the white diodes associated with blue pixels may need to be driven with relatively large currents. This can reduce the lifetime of a display.
It would therefore be desirable to be able to provide improved organic light-emitting diode displays such as improved organic light-emitting diode displays using an array of white diodes overlapped by a color filter array.